User's Guide

Review Copy 11-6-10
ThingMagic Micro Family Guide
8
www.JADAKtech.com
Environmental Specifications
Thermal Considerations
There are two ways of mounting the Micro. See Micro Hardware Integration for additional details. One is to
solder the board to the motherboard using its side edge-pads, with the RF shield facing upward. The other
is to use the board-to-board connectors to connect to the motherboard and solder the 4 tabs on the shield
to the motherboard as well. The orientation with the side edge-pads soldered down is best for wicking heat
away from the module.
Most applications involve the module transmitting periodically to inventory tags in the field. The longer the
transmitter is on in relation to its off time (the “duty cycle”), the faster the temperature will rise. The module
will not transmit if the temperature is at a dangerous level but will transmit again as soon as the
temperature drops – often so quickly it is hardly noticeable. Other factors that affect the time before the
module begins to protect itself is the ambient temperature and the power level at which the module is
transmitting. These factors are represented in the following table, which give the typical minutes of
transmission time before thermal protection is enabled.
Thermal Calculations
Mounting
Ambient
Temp (°C)
RF Power
(dBm)
Duty Cycle
%
Time (m) to reach
max temperature
Soldered down
-40
30
98
No restriction
Soldered down
25
23
98
No restriction
Soldered down
25
30
80
No restriction
Soldered down
25
30
90
7.34
Soldered down
25
30
98
5.99
Soldered down
60
23
50
No restriction
Soldered down
60
23
60
7.59
Soldered down
60
23
80
2.24
Soldered down
60
23
98
1.46
Soldered down
60
30
30
No restriction
Soldered down
60
30
50
4.17
Soldered down
60
30
60
1.99
Soldered down
60
30
80
1.11
Soldered down
60
30
98
0.98
Board to board
-40
30
98
No restriction
Board to board
25
23
50
No restriction
Board to board
25
23
60
2.93
Board to board
25
23
80
2.22